Charged particle beam apparatuses have many functions in a plurality of industrial fields, including, but not limited to, inspection of semiconductor devices during manufacturing, exposure systems for lithography, detecting devices and testing systems. Thus, there is a high demand for structuring and inspecting specimens within the micrometer and nanometer scale.
Micrometer and nanometer scale process control, inspection or structuring is often done with charged particle beams, e.g. electron beams, which are generated and focused in charged particle beam devices, such as electron microscopes or electron beam pattern generators. Charged particle beams offer superior spatial resolution compared to, e.g. photon beams, due to their short wavelengths.
The resolution of charged particle beam devices depends inter alia on the charged particle beam optics. One charged particle beam optical element, which is often used in charged particle beam devices, is a magnetic lens or a combined magnetic-electrostatic lens. Generally, a magnetic lens or a magnetic lens component includes two pole pieces, which are energized by an excitation coil. In order to achieve high quality and, thereby, good imaging properties the pole pieces of the lens need to be precisely manufactured and precisely aligned with respect to each other. In particular, a conically shaped objective lens, which is often used as an objective lens being a scanning charged particle beam device, can be difficult to manufacture and to align.